After logout "Add to cart" do not working

The add to cart is not working when I am trying to add a product without login as a member but if I login and then try to add a product by pressing "add to cart" it is working.
I have deactivated all installed plugin and tested but the result is same. What I need is to get functional "add to cart" instead of redirecting to shopping cart page (currently I had to use "buy now" method as an alternative way)